THE ISOTOPIC EVIDENCE OF GAS SOURCE OF THE COLD MINERAL SPRINGS WITH HIGH PCO2 IN WUDALIANCHI

Abstract

Active volcanoes are often associated with thermal springs, but some cold mineral springs exist near the active volcanoes in Wudalianchi, Heilongjiang Province, China, and these cold spas are rich in CO2. Water analysis shows that these HCO3 type mineral springs have higher mineralization degree ( > 1000 mg/L) and are rich in CO2, Fe2+(>20 mg/L), Sr(> 1 mg/L), dissolved Si ( > 2 0 rag/L) with lower temperature(< 10 ~ = and pH < 6.5. Dissolved and evolved gases of all these spas have the same composition, and are composed mainly of CO2 with minor N2 and 02. T